Machine for applying accurately-spaced fastening elements

ABSTRACT

An automatic machine for applying fastening or similar elements such as staples to a workpiece, in a row having accurately predetermined spacings. Cumulative spacing errors are absent. One application is for the insertion of the staples into the tilt rods of shutters. An elongated control element such as a punched steel tape is used to control a pneumatic stapling gun or the like. Holes are punched in the tape at positions corresponding to the locations that the fasteners are to have on the workpiece. One end of the tape is attached to the workpiece and moves with it past the stapling gun. The holes are sensed by a sensitive air pilot valve, which causes the gun to fire when a hole is sensed. The workpiece is moved continuously by a motor and roller. Insertion of a workpiece, such as a wooden rod, starts the machine via a roller-actuated valve. When the workpiece has passed through the machine, this valve releases and stops the machine. The machine is inexpensive, self-contained, and portable. Tapes are easily changed.

United States Patent [191 Arkush, Jr.

[ June 26, 1973 MACHINE FOR APPLYING ACCURATELY-SPACED FASTENING ELEMENTS [76] Inventor: Ellis John Arkush, Jr., 1144 Gleneagles Terrace, Costa Mesa,

Calif. 92627 [22] Filed: Sept. 30, 1971 [211 App]. No.: 185,195

Primary Examiner-Granville Y, Custer, Jr. Attorney-Lawrence Fleming [5 7 ABSTRACT An automatic machine for applying fastening or similar elements such as staples to a workpiece, in a row having accurately predetermined spacings. Cumulative spacing errors are absent. One application is for the insertion of the staples into the tilt rods of shutters. An elongated control element such as a punched steel tape is used to control a pneumatic stapling gun or the'like. Holes are punched in the tape at positions corresponding to the locations that the fasteners are to have on the workpiece. One end of the tape is attached to the workpiece and moves with it past the stapling gun. The holes are sensed by a sensitive air pilot valve, which causes the gun to fire when a hole is sensed. The workpiece is moved continuously by a motor and roller. Insertion of a workpiece, such as a wooden rod, starts the machine via a roller-actuated valve. When the workpiece has passed through the machine, this valve releases and stops the machine. The machine is inexpensive, selfcontained, and portable. Tapes are easily changed.

7 Claims, 3 Drawing Figures MACHINE FOR APPLYING ACCURATELY-SPACED FASTENING ELEMENTS BACKGROUND OF THE INVENTION This invention relates to automatic machines for inserting staples, fasteners, or the like in a workpiece along a line at accurately predetermined spacings.

Certain manufacturing operations require the insertion of a series of fasteners or the like in a row, with accurately predetermined spacings free from cumulative error. An example is found in the manufacture of wooden shutters of the type where the slats are individually pivoted and are all turned together to open or close the shutter. In these, the slats are turned by a tilt rod in which is inserted a row of protruding staples. Each such staple engage s another staple on the leading edge of each slat. The spacing between the staples on the tilt rod must be the same as the spacing of the slats, and there must be no cumulative error in the spacing,

i.e., the staples at the opposite ends of a long row must be exactly as far apart as the corresponding end slats, so that all the slats will move in phase. A cumulative error of 1 percent in a tilt rod for 50 slats on l-inch centers would, for example, be 0.5 inch, an unacceptable amount.

An automatic machine for such purposes commonly employs a stapling'gun or the like mounted on the machine frame, and a means for advancing the workpiece along opposite the gun. Control means cause the gun to fire, inserting a staple into the workpiece, at predetermined points along the travel of the workpiece, for example,one per inc-h.

Prior machines employ such expedients as clamping the workpiece to a rack which is advanced linearly by a pinion, the firing of the gun being controlled as a function of the rotation of the pinion. In some, the con- I trol is derived from the'spacing of previously inserted staples, which may lead to cumulative errors in spacing. Another prior expedient is to clamp the workpiece to v a ratchet bar, whose teeth spacing determines the sta- SUMMARY OF THE INVENTION The present invention is an automatic machine for inserting fasteners or like elements into a workpiece, in a row with accurate predetermined spacing. A preferred form of the machine inserts staples part way into a wood rod, such as a tilt rod for a shutter assembly. The staples are inserted by a pneumatic stapling'gun of suitable known type. The workpiece is advanced axially along under the gun by suitable means such as a knurled wheel rotated by a motor. Its motion is continuous. The motor may be started automatically in response to the insertion of the workpiece into the machine, as by means of a roller which the workpiece forces out of the way. The roller may operate a switch or valve to start the motor.

Advancing axially along past the stapling gun, the forward end of the workpiece may now pick up or engage a suitable fitting or cap which is affixed to the end of a steel tape, the tape then advancing with the workpiece. I-Ioles in the tape are used to control where the staples are inserted. The holes are punched in the tape at points along its length corresponding to where the staples are to go in the workpiece.

A hole-sensing station is provided, preferably equipped with a sensitive air pilot valve actuated by a small inward displacement of a protruding ball. Such valves are sold commercially. The ball normally contacts the tape. When a hole comes by, the ball drops into it (urged by light spring pressure), actuating the sensitive valve. This valve is in turn connected so as to operate the actuator valve of the pneumatic stapling gun, which thereupon fires and inserts a staple into the workpiece. Preferably, a pressure-actuated directional control valve is connected between the sensitive pilot valve and the stapler, to act as a relay.

The tape may be the well-known commercial type of flexible steel measuring tape which is pulled out against a windup spring for use, the spring automatically rolling it back into its container when it is released.

While such a tape is cheap and convenient for the purpose, it'is evident that various other sorts of elongated elements could be used, such as a flexible cable or a flat bar; it is also apparent that any kind of local deformity or mark could be used on such an element besides a hole, so long as it is capable of being sensed by artificial means. Similarly, it will be evident that other means of drive and control could be used besides pneumatic, such as electrical. An all-pneumatic system is, however, preferred.

It will beseen that the machine will insert staples in the workpiece at points along its length whose linear locations correspond accurately to the locations of the holes in the tape. While the more common requirement is for uniform spacing, the tape can be punched to give any program desired, and is inexpensive and easily changed or replaced.

DETAILED DESCRIPTION In the drawing:

FIG. 1 is a perspective view of a machine according to the invention; v

FIG. 2 is a sectional detail view of the sensing station portion of the machine; and

FIG. 3 is a schematic diagram of the pneumatic circuit of the machine of FIG. 1.

' Referring to FIG. 1, the frame or base plate of the machine is indicated at 40. A portion of a wooden-rod workpiece is shown at 1, in which some staples 3 have been inserted by a pneumatic stapling gun 2 of any suitable known type.

The workpiece 1 is moved to the left past the gun 2, as indicated by arrows 1', by frictional engagement with a knurled drive wheel 4 which is rotated at a suitable speed by a motor 5. The motor 5 may be an ordinary air-powered motor with a built-in gear reduction.

A roller 6 is provided to hold the workpiece 1 against the drive wheel 4 The shaft of roller 6 is secured to a slidable element 7 of any suitable shape, which slides ina direction perpendicular to workpiece l in a suitable portion of frame 40 as indicated at 8, and is urged toward the workpiece 1 by a spring 9. The roller 6 could alternatively be mounted on a pivoted springloaded arm of suitable design.

Bearing on the roller 6 is the actuating arm of an air valve 11. When arm 10 moves toward the valve body 11, it opens the valve. When workpiece l is absent, spring 9 pushes roller 6 substantially in contact with drive wheel 9. Arm 10 is then in a position that closes valve 11, and the machine is stopped. When a workpiece 1 is inserted into the machine, it pushes roller 6 away, in the direction of arrow 6'. Roller 6 in turn moves arm 10 in the same direction, which opens the air valve 11 and starts the machine. Valve 11 controls the compressed air supply to the whole machine, as will be described presently in connection with FIG. 3.

Referring again to FIG. 1, workpiece 1 passes under the head 41 of the stapling gun 2, and on to the left through a sensing station, indicated as an assembly at 20. Past the sensing station 20 the workpiece 1 is engaged by a fitting 13 on the end of a steel tape 12, which may cover it like a cap.

Tape 12 is preferably of the commercial springretracted type referred to above. Its case is shown at 14. Before workpiece 1 is inserted in the machine, tape 12 will be retracted by the spring in case 14 until cap 13 is stopped by a bracket 22 at the sensing station 20. As the workpiece 1 advances through, its end engages the fitting or cap 13, and draws the tape along with itself.

The holes in the tape are indicated at 15. As each hole passes by the sensing station 20, the sensitive pilot valve 21 senses its presence, and operates to actuate the gun 2, which inserts a staple 3 or the like into the workpiece 1.

Referring now to FIG. 2, which shows the sensing station 20 in more detail, it will be seen that the workpiece 1 passes between the back side of a bracket or spacer 22 (also shown in FIG. 1) and a fixed guide roller 23. The tape 12 passes across the opposite side of the spacer 22, and is held against it by the light pressure of a spring in valve 21 (not shown) which presses the ball 24 against the tape.

When one of the holes comes opposite the ball 24, the ball goes into the hole. Opposite the ball 24 there is a hole or depression 25 in the spacer 22, so that the ball 24 can move forward a distance somewhat greater than the thickness of the tape 12.

In the particular preferred form of the invention shown, the stapling gun 2 is of the type that is inhibited from firing by the presense of air pressure at an actuator valve or firing valve fitting 35, and fires when the pressure is removed. Between the sensitive pilot valve 21 and the gun fitting 35 which leads to its internal actuator valve (not shown), there may be interposed a pressure-actuated directional control valve 16, which acts as a relay. Compressed air from the supply line 31 (shown more completely in FIG. 3) is available to the directional control valve 16, which normally transmits this pressure to the gun fitting 35 and inhibits the gun 2 from firing. Pressure from the sensitive pilot valve 21 may, through a line 34, actuate the directional control valve 16 in a manner to keep it transmitting pressure to the gun actuator or firing valve fitting 35. When the sensitive pilot valve 21 is actuated by the displacement of ball 25 into a hole 15, however, it may then release the pressure in line 34, which in turn will actuate valve 16 in the other direction, releasing the pressure from gun fitting 35 (venting it to the atmosphere) and thus firing the gun and inserting a staple into workpiece 1. Valve 16 may have a vent port (not shown) for such release.

Should the gun 2 be chosen as a type that fires upon the application of air pressure to a firing valve or actuator valve port such as 35, rather than upon its removal, suitable valves and connections at 21 and 16 may obviously be chosen so that the gun will fire when valve 21 senses a hole such as 15, so that the overall operation will be as before.

FIG. 3 shows a pneumatic circuit in schematic form for greater clarity. Compressed air at, typically, or psi pressure, is supplied at 33 from an external source, to a manually operated valve 19 which serves as a main on-off switch. From this valve there proceeds a line to a conventional air filter and oiler 18. Thence the air proceeds through line 32 to the rolleractuated valve 1 1 which controls the rest of the system. From valve 11, the main air supply line 31 extends to the staple gun, the motor, and the gun control valves 16 and 21. A branch 37 extends from supply line 31 through a pressure regulator 17 to the air motor 5. The main air supply fitting 36 on gun 2 (for operating the stapling piston) is also connected to line 31. Normally open directional control valve 16 takes air from line 31 and normally transmits its pressure to gun firing actuator fitting 35, keeping the gun from firing. Lastly, air from line 31 is piped to the sensitive pilot valve 21 for normal admissiOn to the actuator fitting of directional control valve 16. When valve 21 is actuated by a tape hole 15, it removes pressure from line 34, which actuates control valve 16 to vent the pressure from gun actuator valve fitting 35, firing .the staple gun.

A successful working model of this machine employed the following commercial components:

Staple gun 2: Model FAX3809, manufactured by Spotnails, Inc., Rolling Meadows, Ill.

Directional control valve 16: Type L-lO, Mead Fluid Dynamics, Chicago, Ill.

Sensitive pilot valve 21: Type HTB 40-D Hair Trigger Light Touch Air Pilot Valve," same manufacturer.

Roller-actuated valve 11: Type 203A, Aro Corporation.

It will be understood that the specific embodiment of the invention just described is only illustrative. The principles of the invention could be applied to other operations besides inserting staples, and the various sensing, driving, and control functions performed electrically as well as pneumatically.

In the claims, the term gun is used to mean any kind of apparatus to apply fasteners or the like to a workpiece, e.g., nails, staples, screws, or a spot-welder, punch, or drill, the gun being capable of actuation, i.e., firing, by a pneumatic, mechanical, or electrical command signal.

It will be seen that a machine according to the invention may be built to be compact, self-contained, and portable. Tapes may be punched with any desired linear arrangement of holes, and may be easily changed or replaced.

I claim:

1. An automatic machine for applying fastening elements along a workpiece at accurate predetermined spaced positions, comprising:

a gun to apply said fastening elements;

drive means to move said workpiece continuously past said gun without stopping during the application of said fastening elements;

a measuring element independent of said drive means having an extendable portion extendable parallel to said workpiece and having locationmarks and a quick-detachable fitting engagable with a single portion of said workpiece,

said measuring element being mounted on said machine as a part thereof and being adapted to be changed to suit varying spacing requirements; and

a sensing station disposed to sense said marks and cause the rapid actuation of said gun when a mark is sensed;

said workpiece when in motion engaging said fitting and advancing said extendable portion along in fixed relation to itself,

whereby said fastening elements are applied rapidly in spaced relations determined accurately by said marks.

2. A machine as in claim 1, wherein said measuring element is a flexible spring-retracted tape.

3. A machine as in claim 1, wherein said marks are holes.

4. A machine as in claim 1, wherein: said measuring element is a spring-retractable tape having said fitting substantially at its outer end,

said marks are holes, and

said fitting is positioned to-automatically engage the end of said workpiece as it advances past said sensing station, said tape then being drawn along parallel to said workpiece.

5. A machine as in claim 4, wherein:

said workpiece is elongated,

said means to drive it comprises a wheei driven by a motor engaging one side of said workpiece,

a backup roller engages the other side of said workpiece, and 1 said backup roller actuates means to start said motor.

6. A machine as in claim 5, wherein:

said gun is powered and triggered by compressed air,

and

said sensing station comprises a sensitive air valve having an actuating element sensing said holes mechanically,

said valve causing the firing of said gun through pneumatic means when a hole passes said actuating element.

7. A machine as in claim 5, wherein said workpiece is a rod-like wood element, and said gun inserts staples. 

1. An automatic machine for applying fastening elements along a workpiece at accurate predetermined spaced positions, comprising: a gun to apply said fastening elements; drive means to move said workpiece continuously past said gun without stopping during the application of said fastening elements; a measuring element independent of said drive means having an extendable portion extendable parallel to said workpiece and having location marks and a quick-detachable fitting engagable with a single portion of said workpiece, said measuring element being mounted on said machine as a part thereof and being adapted to be changed to suit varying spacing requirements; and a sensing station disposed to sense said marks and cause the rapid actuation of said gun when a mark is sensed; said workpiece when in motion engaging said fitting and advancing said extendable portion along in fixed relation to itself, whereby said fastening elements are applied rapidly in spaced relations determined accurately by said marks.
 2. A machine as in claim 1, wherein said measuring element is a flexible spring-retracted tape.
 3. A machine as in claim 1, wherein said marks are holes.
 4. A machine as in claim 1, wherein: said measuriNg element is a spring-retractable tape having said fitting substantially at its outer end, said marks are holes, and said fitting is positioned to automatically engage the end of said workpiece as it advances past said sensing station, said tape then being drawn along parallel to said workpiece.
 5. A machine as in claim 4, wherein: said workpiece is elongated, said means to drive it comprises a wheel driven by a motor engaging one side of said workpiece, a backup roller engages the other side of said workpiece, and said backup roller actuates means to start said motor.
 6. A machine as in claim 5, wherein: said gun is powered and triggered by compressed air, and said sensing station comprises a sensitive air valve having an actuating element sensing said holes mechanically, said valve causing the firing of said gun through pneumatic means when a hole passes said actuating element.
 7. A machine as in claim 5, wherein said workpiece is a rod-like wood element, and said gun inserts staples. 